Lithium-ion battery temperature detection system

Abstract

A lithium battery temperature detection system of the present invention comprises: a temperature alarm module, a temperature detection module, and a battery pack; the temperature detection module comprises a plurality of temperature detection sensors, and the plurality of temperature detection sensors are used to detect the internal temperature of the battery pack; the temperature alarm module is electrically connected to the plurality of temperature detection sensors, and the temperature alarm module is used to receive temperature data of the plurality of temperature detection sensors; when the temperature data of one of the temperature detection sensors reaches a preset threshold, the temperature alarm module triggers an alarm; an explosion-proof vent valve is installed on the shell of the battery pack. A lithium battery temperature detection system of the present invention improves the traditional explosion-proof vent valve, improves its reliability of rapid pressure relief, and thereby improves the overall performance of the lithium battery temperature detection system.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a lithium ion battery temperature detection system. Background Art

[0002] As the mainstream energy storage technology widely used in modern electronic devices and electric vehicles, lithium batteries have attracted widespread attention, and their excellent energy density has become the focus of much attention. However, the failure problem of lithium batteries has hindered further development. Lithium battery failure not only brings economic losses, but also comes with safety hazards. Lithium battery failure can be summarized into two main types of problems: performance failure and safety failure. Performance failure refers to the degradation of battery performance or abnormal use due to specific root causes, often accompanied by problems such as capacity degradation and increased internal resistance. Safety failure involves safety hazards such as thermal runaway, lithium dendrites, and leakage that may occur in batteries under special circumstances.

[0003] During service, lithium-ion batteries are prone to thermal runaway and stress strain due to mechanical, electrical and thermal factors, which pose a major threat to the overall safety of many battery systems. The temperature of lithium-ion batteries will increase due to lithium ion migration and electrochemical reactions. Generally speaking, under normal circumstances, this temperature increase will not have an adverse effect on the performance and safety of lithium-ion batteries. However, if the abuse of the battery causes it to generate additional heat, the internal electrochemical side reactions will intensify, generating a large amount of heat and flammable gases, and ultimately leading to thermal runaway events. Strain in lithium batteries is usually caused by electrochemical-mechanical behavior and is accompanied by volume deformation under short-term cycling, long-term degradation and abuse conditions. In particular, during the cycling of lithium batteries, lithium ions are embedded and extracted in the positive and negative electrode lattices, causing non-negligible volume changes. In response to such safety hazards in lithium-ion battery systems, researchers have developed a variety of methods, and temperature detection is one of them.

[0004] Temperature accumulation generally occurs as heat is generated by the electrochemical process in lithium batteries. In this process, the heat generated by entropy change is reversible, while the heat caused by overpotential (including charge transfer, ohmic loss and mass transfer limitation) is irreversible. In addition, heat is dissipated to the external environment through multiple pathways such as conduction, convection and radiation. The appropriate operating temperature of lithium batteries depends on the dynamic balance between heat generation and heat dissipation. Otherwise, excessive heat generation will lead to capacity loss, self-discharge, electrical balance, and even thermal runaway. In addition, the temperature increase caused by abnormal heating will also cause side reactions such as SEI decomposition, which will irreversibly shorten the battery life. Therefore, it is crucial to detect the temperature during the operation of lithium batteries.

[0005] During the design of the lithium battery temperature detection system, an explosion-proof vent valve is usually installed on the battery pack. Under normal conditions, the explosion-proof vent valve is used to achieve the balance of air pressure inside and outside the battery pack. Under abnormal conditions such as thermal runaway, the explosion-proof vent valve is used to achieve rapid pressure relief of the battery pack. For example, the prior art (CN 206159577U) discloses an explosion-proof waterproof breathable valve, which is mentioned in the specific implementation of its specification as follows: when the pressure inside the cavity of the device is less than the pressure of the spring 212 of the piston rod 2, the gas inside and outside the cavity flows freely through the exhaust hole 211 on the side of the piston rod 2 through the waterproof breathable membrane 4, and the gas flows from the side with high pressure to the side with low pressure, that is, when the pressure inside the cavity of the device is greater than the pressure outside the cavity of the device, the gas is discharged from the exhaust hole 211 on the side of the piston rod 2 through the waterproof breathable membrane 4, and when the pressure inside the cavity is less than the external pressure, the gas will enter the device cavity from the waterproof breathable membrane 4, thereby achieving air pressure balance; when the pressure inside the cavity is greater than or equal to a certain value, the internal pressure will push the piston rod 2 outward, and the gas will be directly connected to the outside world, achieving rapid pressure relief, thereby quickly reducing the pressure inside the cavity of the device, thereby preventing the cavity from exploding. When the pressure inside the cavity is lower than a certain value, the piston rod 2 is reset to a normal closed state by the action of the spring 212.

[0006] The explosion-proof waterproof breathable valve disclosed in the above-mentioned prior art (CN 206159577 U) also has a technical problem during use: a waterproof ring 3 is arranged between the plug-in end 12 and the piston rod 2, and the waterproof ring 3 will age during long-term use. The rubber colloid of the waterproof ring 3 after aging will become very viscous. When the piston rod 2 is inactive for a long time, the piston rod 2 can easily be firmly bonded to the plug-in end 12 through the waterproof ring 3, so that the piston rod 2 cannot move smoothly, thereby losing the function of rapid pressure relief.

[0007] Therefore, it is necessary to improve the traditional explosion-proof vent valve within the framework of the lithium battery temperature detection system to improve its reliability of rapid pressure relief, thereby improving the overall performance of the lithium battery temperature detection system. Summary of the invention

[0008] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a lithium battery temperature detection system to improve the traditional explosion-proof vent valve, improve its reliability of rapid pressure relief, and thereby improve the overall performance of the lithium battery temperature detection system.

[0009] The objective of the present invention is achieved through the following technical solutions:

[0010] A lithium battery temperature detection system, comprising: a temperature alarm module, a temperature detection module, and a battery pack;

[0011] The temperature detection module includes a plurality of temperature detection sensors, and the plurality of temperature detection sensors are used to detect the internal temperature of the battery pack;

[0012] The temperature alarm module is electrically connected to the plurality of temperature detection sensors, and is used to receive temperature data of the plurality of temperature detection sensors; when the temperature data of one of the temperature detection sensors reaches a preset threshold, the temperature alarm module triggers an alarm;

[0013] An explosion-proof vent valve is installed on the shell of the battery pack.

[0014] In one of the embodiments, the lithium battery temperature detection system further includes a heat dissipation module for dissipating heat inside the battery pack.

[0015] In one of the embodiments, the heat dissipation module includes an air cooling device.

[0016] In one of the embodiments, the heat dissipation module includes a liquid cooling device.

[0017] In one of the embodiments, the heat dissipation module includes a heat pipe cooling device.

[0018] In one embodiment, the explosion-proof vent valve comprises: a body, a cover, a piston, and a spring;

[0019] The body is a hollow columnar structure, and has a top connection part and a bottom connection part. A sealing ring is provided in the inner cavity of the body, and the sealing ring is located between the top connection part and the bottom connection part. An exhaust port is provided on the side wall of the body near the top connection part, and an air inlet is provided on the end surface of the body near the bottom connection part.

[0020] The cover body is screwed on the top connecting part, and the piston is arranged on the cover body through the spring, and the spring is used to provide elastic force for the piston so that the piston is pressed on the sealing ring; the piston is provided with an air hole, and the air hole is attached with an air-permeable film;

[0021] The sealing ring is provided with an annular receiving groove, an easy-to-remove ring is provided at the notch of the annular receiving groove, a receiving cavity is formed between the easy-to-remove ring and the annular receiving groove, and paraffin is poured into the receiving cavity; a heat-receiving ring groove is provided in the inner cavity of the body, and the heat-receiving ring groove is located at the bottom of the sealing ring;

[0022] An annular mounting groove is provided on the piston, an inner sealing ring is provided in the annular mounting groove, and the inner sealing ring is pressed on the easy-to-detach ring.

[0023] In one of the embodiments, the easy-to-remove ring is an aluminum plate structure, and the easy-to-remove ring is clamped on the edge of the notch of the annular receiving groove.

[0024] In one of the embodiments, an outer sealing ring is provided on the side wall of the body at the bottom layer connection portion.

[0025] A lithium battery temperature detection system of the present invention improves a traditional explosion-proof vent valve, thereby increasing the reliability of its rapid pressure relief, thereby improving the overall performance of the lithium battery temperature detection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A module diagram of a lithium battery temperature detection system according to an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of installing an explosion-proof vent valve on a battery pack;

[0029] Figure 3 for Figure 2 A three-dimensional diagram of the explosion-proof vent valve shown;

[0030] Figure 4 for Figure 2 The plan view of the explosion-proof vent valve shown;

[0031] Figure 5 for Figure 3 A cross-sectional view of the cover of the explosion-proof vent valve shown;

[0032] Figure 6 for Figure 3 A cross-sectional view of the body of the explosion-proof vent valve shown;

[0033] Figure 7 for Figure 3 A cross-sectional view of an explosion-proof vent valve is shown. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0035] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] like Figure 1 As shown, the present invention discloses a lithium battery temperature detection system 10, including: a temperature alarm module 20, a temperature detection module 30, and a battery pack 40.

[0038] like Figure 1 As shown, the temperature detection module 30 includes a plurality of temperature detection sensors 31 , and the plurality of temperature detection sensors 31 are used to detect the internal temperature of the battery pack 40 .

[0039] like Figure 1 As shown, the temperature alarm module 20 is electrically connected to multiple temperature detection sensors 31, and the temperature alarm module 20 is used to receive temperature data from multiple temperature detection sensors 31; when the temperature data of one of the temperature detection sensors 31 reaches a preset threshold, the temperature alarm module 20 triggers an alarm.

[0040] like Figure 1 and Figure 2 As shown, an explosion-proof vent valve 50 is installed on the housing of the battery pack 40 .

[0041] like Figure 1 As shown, further, the lithium battery temperature detection system 10 also includes a heat dissipation module 60 for dissipating heat inside the battery pack 40. Preferably, the heat dissipation module 60 is an air cooling device and a liquid cooling device. Of course, in other embodiments, the heat dissipation module 60 can also be a heat pipe cooling device.

[0042] Next, the specific structure of the explosion-proof vent valve 50 is described:

[0043] like Figure 3 , Figure 4 and Figure 5 As shown, the explosion-proof air valve 50 includes: a body 100 , a cover 200 , a piston 300 , and a spring 400 .

[0044] like Figure 6 As shown, the main body 100 is a hollow cylindrical structure, and the main body 100 has a top connection part 110 and a bottom connection part 120. A sealing ring 130 is provided in the inner cavity of the main body 100, and the sealing ring 130 is located between the top connection part 110 and the bottom connection part 120; an exhaust port 101 is provided on the side wall of the main body 100 near the top connection part 110, and an air inlet 102 is provided on the end face of the main body 100 near the bottom connection part 120.

[0045] like Figure 5 and Figure 7 As shown, the cover body 200 is screwed on the top connection part 110, and the piston 300 is arranged on the cover body 200 through the spring 400. The spring 400 is used to provide elastic force for the piston 300 so that the piston 300 is pressed on the sealing ring 130; a ventilation hole 310 is opened on the piston 300, and a ventilation film 320 is attached to the ventilation hole 310.

[0046] like Figure 6 As shown, the sealing ring 130 is provided with an annular receiving groove 131, and an easy-to-remove ring 500 is provided at the notch of the annular receiving groove 131. A receiving cavity is formed between the easy-to-remove ring 500 and the annular receiving groove 131, and paraffin 600 (such as Figure 7 A heat-receiving ring groove 103 is provided in the inner cavity of the main body 100, and the heat-receiving ring groove 103 is located at the bottom of the sealing ring 130.

[0047] like Figure 5 As shown, the piston 300 is provided with an annular mounting groove 330, in which an inner sealing ring 700 is provided, and the inner sealing ring 700 is pressed on the easy-to-remove ring 500 (as shown in FIG. Figure 7 shown).

[0048] Next, the working principle of the explosion-proof vent valve 50 of the above structure is described:

[0049] like Figure 7 As shown, in a normal state, the spring 400 provides elastic force for the piston 300, so that the piston 300 is pressed on the sealing ring 130, specifically, the inner sealing ring 700 is pressed on the easy-to-release ring 500. In this state, the airflow inside and outside the battery pack is normally circulated through the exhaust port 101 and the air hole 310, and the airflow can pass through the air permeable membrane 320 normally. The air permeable membrane 320 is used to prevent external impurities such as dust and water vapor from entering the battery pack;

[0050] When the battery pack experiences thermal runaway, the gas inside the battery pack expands rapidly, pushing the piston 300 (the spring 400 is compressed). The piston 300 no longer presses on the sealing ring 130, thereby providing a larger opening for rapid gas pressure relief.

[0051] Thermal runaway of the battery pack is a rare accident. Since the inner sealing ring 700 is made of rubber, it is very easy to age and the colloid becomes very viscous. When the inner sealing ring 700 is pressed against the easy-to-detach ring 500 for a long time, the inner sealing ring 700 will be firmly adhered to the easy-to-detach ring 500. In this case, the piston 300 of the present invention can also be easily separated from the sealing ring 130. The specific explanation is as follows:

[0052] On the one hand, unlike the conventional method (for example, in the prior art CN 206159577 U, a waterproof ring is arranged in the plug-in end 12), the present invention provides an annular mounting groove 330 on the piston 300, and installs the inner sealing ring 700 in the annular mounting groove 330 of the piston 300. In this way, even if the inner sealing ring 700 is firmly adhered to the easy-to-detach ring 500, under the impact force of the gas inside the battery pack, the inner sealing ring 700 is likely to be separated from the annular mounting groove 330, thereby realizing the separation of the piston 300 and the sealing ring 130; lubricating oil can be applied to the groove body of the annular mounting groove 330, so that the inner sealing ring 700 is easier to be separated from the annular mounting groove 330;

[0053] On the other hand, when the battery pack is in thermal runaway, the depressurized gas in the battery pack may reach above 60°C, which is sufficient to melt the solid paraffin in the accommodating cavity and transform into liquid paraffin. After the paraffin transforms from solid to liquid, its volume increases, thereby generating sufficient pressure to push the easy-to-remove ring 500, so that the easy-to-remove ring 500 is separated from the annular receiving groove 131. In this way, the easy-to-remove ring 500, the inner sealing ring 700 and the piston 300 are separated from the sealing ring 130 as a whole, thereby achieving the pressure relief function.

[0054] It should be noted that in the present invention, a heat ring groove 103 is provided in the inner cavity of the body 100, and the heat ring groove 103 is located at the bottom of the sealing ring 130. The pressure relief gas can reach the bottom of the sealing ring 130 through the heat ring groove 103, so that the paraffin 600 in the annular receiving groove 131 is more easily melted by heat;

[0055] It can be seen that in order to solve the technical problem of the inner sealing ring 700 being firmly adhered due to aging and viscosity, the present invention provides two protection measures. The first protection measure is to install the inner sealing ring 700 in the annular mounting groove 330 of the cover body 200. If the first protection measure fails to work, the second protection measure is to inject paraffin into the accommodating cavity and install the easy-to-release ring 500, thereby fully ensuring the effective separation of the piston 300 of the battery pack in the thermal runaway state, providing safety protection for pressure relief.

[0056] In this embodiment, the easy-to-remove ring 500 is an aluminum plate structure, and the easy-to-remove ring 500 is clamped on the edge of the notch of the annular receiving groove 131. The easy-to-remove ring 500 of the aluminum plate structure has good stability and high structural strength. In other embodiments, the easy-to-remove ring 500 can also be a plastic plate structure.

[0057] like Figure 6 As shown, in this embodiment, an outer sealing ring 800 is provided on the side wall of the body 100 at the bottom connection portion 120 , and the outer sealing ring 800 is used to improve the connection sealing between the body 100 and the battery pack.

[0058] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A lithium battery temperature detection system, characterized in that: include: Temperature alarm module, temperature detection module, battery pack; The temperature detection module includes a plurality of temperature detection sensors, and the plurality of temperature detection sensors are used to detect the internal temperature of the battery pack; The temperature alarm module is electrically connected to the plurality of temperature detection sensors, and is used to receive temperature data of the plurality of temperature detection sensors; when the temperature data of one of the temperature detection sensors reaches a preset threshold, the temperature alarm module triggers an alarm; An explosion-proof vent valve is installed on the shell of the battery pack; The explosion-proof air-permeable valve comprises: a body, a cover, a piston, and a spring; The body is a hollow columnar structure, and has a top connection part and a bottom connection part. A sealing ring is provided in the inner cavity of the body, and the sealing ring is located between the top connection part and the bottom connection part. An exhaust port is provided on the side wall of the body near the top connection part, and an air inlet is provided on the end surface of the body near the bottom connection part. The cover body is screwed on the top connecting part, and the piston is arranged on the cover body through the spring, and the spring is used to provide elastic force for the piston so that the piston is pressed on the sealing ring; the piston is provided with an air hole, and the air hole is attached with an air-permeable film; The sealing ring is provided with an annular receiving groove, an easy-to-remove ring is provided at the notch of the annular receiving groove, a receiving cavity is formed between the easy-to-remove ring and the annular receiving groove, and paraffin is poured into the receiving cavity; a heat-receiving ring groove is provided in the inner cavity of the body, and the heat-receiving ring groove is located at the bottom of the sealing ring; The piston is provided with an annular mounting groove, in which an inner sealing ring is arranged, and the inner sealing ring is pressed on the easy-to-detach ring; lubricating oil is applied to the groove body of the annular mounting groove.

2. The lithium battery temperature detection system according to claim 1, characterized in that: The lithium battery temperature detection system also includes a heat dissipation module for dissipating heat inside the battery pack.

3. The lithium battery temperature detection system according to claim 2, characterized in that: The heat dissipation module includes an air cooling device.

4. The lithium battery temperature detection system according to claim 2, characterized in that: The heat dissipation module includes a liquid cooling device.

5. The lithium battery temperature detection system according to claim 2, characterized in that: The heat dissipation module includes a heat pipe cooling device.

6. The lithium battery temperature detection system according to claim 1, characterized in that: The easy-to-remove ring is an aluminum plate structure, and the easy-to-remove ring is clamped on the notch edge of the annular receiving groove.

7. The lithium battery temperature detection system according to claim 1, characterized in that: An outer sealing ring is provided on the side wall of the body at the bottom layer connecting portion.

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